It took nearly a century for scientists to detect gravitational waves — ripples in spacetime caused by powerful cosmic events. Even a major event like the merger of two black holes creates only a tiny change in spacetime, requiring highly sensitive interferometers to detect these waves. The breakthrough detection of gravitational waves in 2015 has now inspired a search for even finer variations in spacetime, which could help us understand more about the gravitational field's fundamental nature.

An important focus now is on detecting 'spacetime fluctuations' — small, random changes in the structure of spacetime predicted by some quantum and semiclassical gravity models. The statistical properties of these fluctuations could reveal insights into their fundamental nature and origins. In my talk, I will discuss the current experimental efforts in the search for these spacetime fluctuations. I will also explain how these experiments aim to capture specific, detectable 'signatures' of different types of fluctuations.